February 29, 201610 yr I had to do some maintenance on my bike which required removing the three 22 Nt.. bolts. When I re-torqued the bolts back up to 22 Nt. , I stripped the thread on 2 of the frame holes. The local bike shop now has my bike for repair and they say I should only have tightened to about 18 max. My first experience with a torque wrench, so I suppose we learn from our mistakes but does 18 Nt. sound about right ?
February 29, 201610 yr If your torque wrench has not been used for a while? I always operate and trip mine a couple of times at a low torque before using it at the correct setting.
March 1, 201610 yr If your torque wrench has not been used for a while? I always operate and trip mine a couple of times at a low torque before using it at the correct setting. This and make sure your torque wrench is set at zero when stored. 22nm of torque should not have damaged your threads on the Sduro.
March 1, 201610 yr Author What bolts ? And does it state 22nm on the bolt The 3 bolts that hold the motor into the frame. Yes each says 22 nm around the head of the bolt.
March 1, 201610 yr What sort of torque wrench is it? You can get away with cheap tools for some jobs, but a torque wrench is a precision instrument, so needs to be good.
March 1, 201610 yr I'm not an aficionado of torque wrenches but I wonder if you greased the thread and if so if that would allow a false reading? Dave.
March 1, 201610 yr Author What sort of torque wrench is it? You can get away with cheap tools for some jobs, but a torque wrench is a precision instrument, so needs to be good. I used the Lifeline Essential Torque Wrench from Wiggle. It was only £27 but had very good reviews. I've sent it back because I think this caused the problem. I tried it at 5 nm , it didn't release so I pulled harder. I then tried it on an old lawn mower and it never released on any setting. So I think I over torqued it just on 5 nm with that piece of junk. I'm not an aficionado of torque wrenches but I wonder if you greased the thread and if so if that would allow a false reading? Dave. Good point, I did grease the thread. Would that have made a difference ?
March 1, 201610 yr Torque wrenches for bicycles are a problem. One that reads low enough for delicate fixings - particularly into a carbon frame - will not read high enough for the bigger bolts which need more grunt. Thus you need may need two. As you've discovered, thirty quid wrenches will not do the job. You need to spend at least twice that. The alternative is just use feel to nip up bolts. I would back my ability to do that on a steel or aluminium bike, but might have to bite the bullet and buy a decent wrench - or two - if I ever had to work on a carbon frame.
March 1, 201610 yr you need to make sure that you recognize the click of the torque wrench before using for real. Even when I trust the tool, I always set the torque to 5NM to make sure I know the click. No way you can strip anything with 5NM and you know how it feel like. If the bolt needs 22NM (which is quite high really, similar to 8mm crank bolts), test again at 10NM, and again at 15NM before setting it for 22NM.
March 1, 201610 yr you need to make sure that you recognize the click of the torque wrench before using for real. Even when I trust the tool, I always set the torque to 5NM to make sure I know the click. No way you can strip anything with 5NM and you know how it feel like. If the bolt needs 22NM (which is quite high really, similar to 8mm crank bolts), test again at 10NM, and again at 15NM before setting it for 22NM. I thought 22NM was a lot. The OP says that figure was stamped on the bolt. I suspect the 22NM is a maximum safe load for the bolt, rather than the correct torque for the application.
March 1, 201610 yr I thought those 3 bolts are M6 going into thread inserts, I wouldn't go over 15NM with them.
March 1, 201610 yr . Good point, I did grease the thread. Would that have made a difference ? I think it might, my car handbook warns not to grease wheel bolts as it will affect the torque reading. Someone else on here may know for sure. Dave.
March 1, 201610 yr Out of interest Mossie, is there a threaded/captive insert, or is the thread cut directly into the alloy of the frame? On the KTM range, the head of the bolts, sit within a raised casting on the motor to prevent them from turning, and nylock nuts are used to fasten the bolts against a steel motor plate. A seemingly far superior design, especially given the frequency that the motor is potentially removed for cleaning purposes when used in an off road situation. No real chance of ever screwing a thread, and if you did happen to, you would just replace the bolt/nut. Something that I guess should be done each time any way. Edited March 1, 201610 yr by EddiePJ
March 1, 201610 yr Author Out of interest Mossie, is there a threaded/captive insert, or is the thread cut directly into the alloy of the frame? On the KTM range, the head of the bolts, sit within a raised casting on the motor to prevent them from turning, and nylock nuts are used to fasten the bolts against a steel motor plate. A seemingly far superior design, especially given the frequency that the motor is potentially removed for cleaning purposes when used in an off road situation. No real chance of ever screwing a thread, and if you did happen to, you would just replace the bolt/nut. Something that I guess should be done each time any way. Hi there, the thread is cut directly into the alloy frame. If the bike shop can't repair it, I'm going to have to think of plan B and buy some M6 nuts and bolts and bolt to the outside of the frame bypassing the frame thread. Won't be pretty but it should do the job.
March 1, 201610 yr Not a very good photo, as it doesn't show the correct side of the motor where the bolt heads sit, but this is how the motor is mounted on the KTM. http://s25.postimg.org/dmkvbof27/P1180773.jpg [http://s25.postimg.org/otp461r27/DSCF1136_zpsaxvm0ojl_Copy.jpg Another not so clear shot, looking up towards the motor mount tubes that are built into the frame. Ignore the arrow, it was to indicate something in a spate thread. http://s25.postimg.org/bs3fg72nz/12662592_173392926363583_9204823486862280469_n.jpg Edited March 1, 201610 yr by EddiePJ
March 1, 201610 yr Ah sorry, for some reason I assumed that you had a Bosch motor. I wondered why the cast bolt retainers weren't being used. If you get really stuck, and happen to be located close to either East Grinstead, or Crowborough, I can recommend two highly skilled companies that would be able to sort things out for you.
March 1, 201610 yr Author Ah sorry, for some reason I assumed that you had a Bosch motor. I wondered why the cast bolt retainers weren't being used. If you get really stuck, and happen to be located close to either East Grinstead, or Crowborough, I can recommend two highly skilled companies that would be able to sort things out for you. Ok thanks very much
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